How long ago was your surgery? You get the clicking b/c your muscles
have developed unevenly. Tell your PT so the PT can have you develop
your VMO more. I had my surgery 2/2004 and just recently gotten rid of
the "clicking". Don't leave it alone - you really need to be vigilent
about working to get rid of it. Continued clicking will eat away the
groove of your knee.
Good luck!